Antimicrobial activity of olive leaf extract on selected foodborne pathogens and its effect on thermal resistance of Listeria monocytogenes in sous vide ground beef

Authors : Serap COŞANSU AKDEMİR, Özlem KIYMETLİ

Pages : 236-242

Doi:10.31015/jaefs.2021.2.14

View : 11 | Download : 6

Publication Date : 2021-06-28

Article Type : Research Paper

Abstract :Antimicrobial activity of a commercial olive leaf extract insert ignore into journalissuearticles values(OLE); against Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, Escherichia coli Biotype I, Salmonella Enteritidis and Salmonella Typhimurium was tested by disc diffusion assay. The Gram negative bacteria tested in this study were more sensitive to OLE than Gram negatives. The highest antimicrobial activity was on L. monocytogenes which yielded the largest inhibitions zone. Effect of OLE on thermal resistance of L. monocytogenes was tested both in Tryptic Soy Broth supplemented with 0.6% yeast extract insert ignore into journalissuearticles values(TSBYE); and sous vide packed ground beef. OLE added TSBYE insert ignore into journalissuearticles values(0, 0.5, 1%); tubes and ground beef insert ignore into journalissuearticles values(0, 1%); samples were inoculated with L. monocytogenes insert ignore into journalissuearticles values(7-8 log cfu/ml-g); and heated at 55, 60 and 65°C up to 30, 20 and 7.5 minutes, respectively. Total reductions in TSBYE tubes added with 0.5 and 1% OLE were slightly higher than control tubes insert ignore into journalissuearticles values(0% OLE); for all temperatures. Counts of L. monocytogenes in sous vide packed ground beef samples added with 1% OLE and then cooked at 55°C insert ignore into journalissuearticles values(30 min);, 60°C insert ignore into journalissuearticles values(20 min); and 65°C insert ignore into journalissuearticles values(7.5 min); were 0.31, 1.04 and 0.73 log cfu/g lower than those control samples, respectively. The results indicate that OLE included in formulation may be an additional hurdle to control L. monocytogenes in heat processed ground beef.
Keywords : olive leaf extract, sous vide, antimicrobial activity, Listeria monocytogenes, ground beef